Suction cleaning apparatus and method for operating a suction cleaning apparatus

ABSTRACT

Provided is a suction cleaning apparatus including an acting device for acting on an area to be cleaned, a suction unit device for generating a suction flow, and a liquid separator, wherein the liquid separator has a chamber having a peripheral wall and a rotor which is arranged in the chamber so as to be rotatable about a rotational axis, wherein at least one outlet opening for liquid is arranged on the peripheral wall, and wherein a holding tank for liquid is provided which is fluidically connected to the at least one outlet opening for liquid.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of international application number PCT/EP2021/068225, filed on Jul. 1, 2021, and claims the benefit of German application number 10 2020 118 595.2, filed on Jul. 14, 2020, which are incorporated herein by reference in their entirety and for all purposes.

BACKGROUND OF THE INVENTION

The invention relates to a suction cleaning apparatus comprising an acting device for acting on an area to be cleaned, a suction unit device for generating a suction flow, and a liquid separator.

The invention also relates to a method for operating a suction cleaning apparatus.

A suction cleaning apparatus of this kind is used in particular for surface cleaning. For example, a carpet or upholstery, a window pane, or a hard floor surface may be cleaned depending on the configuration of the suction cleaning apparatus.

US 2010/0050368 A1 discloses a suction and cleaning apparatus having a nozzle, blower means, a clean-water tank, and a water-air separator. A tank for dirty liquid and/or dust is provided. A handle serves for holding the apparatus with one hand. Heating means with a ceramic element for electrical and thermal insulation are also provided.

US 2018/0103813 A1 discloses a water suction apparatus having an air blowing function.

US 2012/0266408 A1 discloses a vacuum cleaner with a rotating separator.

DE 10 2012 110 765 A1 discloses a suction cleaning apparatus with a liquid separator which has a holding container for a liquid, at least one supply line, which leads into the holding container, for a liquid-air mixture, and also at least one removal line, which leads into the holding container, for air, and a rotational body which is arranged inside the holding container and which is mounted rotatably about a rotational axis and comprises at least one propeller element for driving a fluid. A drive is provided, by which the rotational body is rotatable independently of the liquid-air mixture.

EP 2 808 553 A2 discloses a fan wheel.

U.S. Pat. No. 5,599,401 discloses a method for sucking in a liquid which is loaded with dirt.

US 2002/0073504 A1 discloses a liquid extraction apparatus.

WO 2016/054944 A1 discloses a vacuum cleaner for hard surfaces.

WO 2016/054943 A1 likewise discloses a cleaning apparatus for cleaning hard surfaces.

US 2014/0007369 A1 discloses a vacuum cleaner.

U.S. Pat. No. 4,776,058 discloses a portable surface-cleaning suction apparatus for sucking in liquids.

CN 103445717 A discloses a portable suction unit for surface cleaning.

In accordance with an embodiment of the invention, a suction cleaning apparatus of the kind described at the outset is provided, which has an effective cleaning function alongside a compact construction.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the invention, provision is made that in a suction cleaning apparatus the liquid separator has a chamber having a peripheral wall and a rotor which is arranged in the chamber so as to be rotatable about a rotational axis, that at least one outlet opening for liquid is arranged on the peripheral wall, and that a holding tank for liquid is provided which is fluidically connected to the at least one outlet opening for liquid.

The suction cleaning apparatus can thus be formed in a compact manner and for example can be realized as a hand-held or hand-guided suction cleaning apparatus. Separated—“de-aired”—liquid can be easily removed from the liquid separator and introduced directly, that is to say with minimized channel length, into the holding tank for liquid.

Due to the rotor in the liquid separator, liquid droplets (which are dirtied when a dirty fluid is sucked in) are propelled by centrifugal forces against the peripheral wall and can then be discharged through the at least one outlet opening.

The holding tank for liquid can thus be positioned in a simple manner on the suction cleaning apparatus, in particular also removably. A relatively large holding volume can be provided for the holding tank for liquid.

The liquid separator may also be used easily as a suction unit device. The rotor can also provide the necessary negative pressure for generation of the suction flow.

Due to the appropriate liquid separator, heavily foaming media can also be sucked in, such as a dirty fluid containing a cleaning agent additive, which is air-laden. A high level of foam breakdown can be achieved in the liquid separator.

The suction cleaning apparatus can be used for different volume flows, as are produced for example when extracting a dirty fluid from textile materials.

High speeds for example in the order of 30,000 revolutions per minute can be achieved for the rotor even alongside a small, compact construction.

A compact construction can be realized so that a hand-held, self-sufficient suction cleaning apparatus can also be formed. For example, it can be used to clean upholstered furniture or car seats effectively.

It is very particularly advantageous if the rotor is part of the suction unit device and is arranged and configured such that it effects a negative pressure during operation of the suction cleaning apparatus to generate the suction flow, and in particular the rotor is formed as an impeller. Liquid separators and suction unit devices are thus formed integrally. In the chamber of the liquid separator, the appropriate negative pressure to suck in the (air-laden) dirty fluid is produced by the rotation of the rotor. The rotor also effects a separation of the sucked-in two-phase flow, specifically the separation of sucked-in air and the dirt-laden liquid. The dirt-laden liquid can in turn collect easily in the holding tank for liquid.

For the same reason, it is favorable if the rotor is arranged and configured such that the liquid separator is formed as a centrifugal separator and, during operation of the suction cleaning apparatus, flings liquid droplets radially outwardly toward the peripheral wall. Due to the at least one outlet opening for liquid, liquid can thus easily be separated from air, and the corresponding dirty liquid can be discharged easily from the chamber and received in the holding tank for liquid. The rotor (fan wheel or impeller) is formed such that the liquid droplets are propelled radially outwardly. For this purpose, corresponding blades are provided. It is usually also provided that a directional component in the peripheral direction is imparted to liquid droplets on the rotor. The radial direction is based here on the rotational axis parallel to the radial direction. The peripheral direction is based correspondingly on the radial direction and the axial direction.

In particular, at least one of the following is provided:

-   -   the rotational axis is oriented parallel at least to a partial         region of the peripheral wall;     -   the chamber is cylindrical or conical-portion-shaped at least in         a partial region;     -   the chamber is at least approximately rotationally symmetrical         to the rotational axis.

An effective possibility for discharging separated (dirtied) liquid is thus created with a compact and space-saving structure.

The approximately rotationally symmetrical form of the chamber is based on the fact that there is a disruption to the rotational symmetry in a partial region of the peripheral wall due to the at least one outlet opening for liquid.

At least one of the following is also favorable:

-   -   a mouth normal of the at least one outlet opening for liquid is         oriented transversely and in particular perpendicularly to the         rotational axis;     -   the at least one outlet opening for liquid is in the form of a         slot;     -   the at least one outlet opening for liquid or a supply region to         the at least one outlet opening for liquid extends over at least         50% and in particular at least 70% and in particular at least         80% of a height (in a height direction parallel to the direction         of rotation) of the peripheral wall;     -   during proper operation of the suction cleaning apparatus for         cleaning a surface that is horizontal with respect to the         direction of gravity, the at least one outlet opening for liquid         and/or the holding tank for liquid lies below and in particular         completely below the rotational axis with respect to the         direction of gravity.

Due to a transverse orientation of a mouth normal of the at least one outlet opening to the rotational axis, a compact construction is produced. In a simple and space-saving manner, separated liquid from the chamber of the liquid separator can be introduced directly into the holding tank for liquid, with minimization of a flow path.

Due to a slot-shaped form of the at least one outlet opening, with in particular exactly one outlet opening being provided, liquid can be discharged from the chamber over a great height region of the peripheral wall.

It is favorable if the at least one outlet opening for liquid or a supply region to the at least one outlet opening for liquid extends over at least 50% and in particular at least 70% and in particular at least 80% (and preferably at least 90%) of a height of the peripheral wall. The height is taken here parallel to the rotational axis. Liquid can thus be discharged from the liquid separator over a great width of the peripheral wall and introduced into the holding tank for liquid. The supply region is a region that is funnel-shaped, for example, in order to improve the supply of liquid to the outlet opening.

In an exemplary embodiment of a suction cleaning apparatus and in particular a hand-held or hand-guided suction cleaning apparatus, the at least one outlet opening for liquid and/or the holding tank for liquid lies (geometrically) below and in particular completely below the rotational axis with respect to the direction of gravity during proper operation for cleaning a horizontal surface. Thus, in this mode of operation, a gravity-driven supply of separated liquid to the at least one outlet opening for liquid can additionally be achieved and the liquid discharge is improved. Furthermore, favorable geometrical conditions are then available, also for other operating modes. However, this does not mean that the suction cleaning apparatus can be operated only in this way. For example, the suction cleaning apparatus can be used to clean vertical surfaces or surfaces inclined relative to the horizontal, such as upholstered backrests.

In one embodiment, the at least one outlet opening for liquid is associated with a supply region, in particular with at least one of the following:

-   -   the supply region has at least one flow region which leads to         the at least one outlet opening for liquid, wherein, in         particular when cleaning a surface which is horizontal with         respect to the direction of gravity, a flow of liquid toward the         at least one outlet opening in the flow region is driven by         gravity;     -   at the supply region, the peripheral wall is inclined relative         to the rotational axis;     -   the supply region is funnel-shaped.

The supply region can improve the discharge of liquid from the chamber of the liquid separator.

In particular, gravity-driven assistance of the discharge of separated liquid from the liquid separator can be achieved.

It is then particularly advantageous if the peripheral wall at the supply region is inclined relative to the rotational axis. For example, the chamber with its peripheral wall is then frustoconical.

In particular, the supply region then forms a funnel which is aligned with the at least one outlet opening for liquid.

A drive motor is advantageously provided which is associated with the chamber and which drives a rotational movement of the rotor, the drive motor in particular being an electric motor. This makes it easy to rotate the rotor as a fan wheel, on the one hand in order to achieve the necessary negative pressure for sucking in the (air-laden) dirty fluid, and on the other hand in order to allow centrifugal separation of liquid droplets.

It is advantageous if a central tube is provided which protrudes into the chamber and which is fluidically connected to the acting device, with an air-laden dirty fluid being introduced into the chamber by means of the central tube. The air-laden dirty fluid can be supplied directly to the rotor by means of the central tube and propelled outwardly by means of the rotor. Thus, on the one hand, a suction flow can be effectively generated, and, on the other hand, centrifugal separation can be effectively achieved.

In particular, at least one of the following is provided:

-   -   the central tube is positioned coaxially with the rotational         axis;     -   the rotor contacts the central tube and in particular contacts         the central tube at or in the region of an end face, or is         spaced apart from the central tube by a gap in particular with a         width of less than 1 mm;     -   the rotor has a central region to which the air-laden dirty         fluid is supplied by means of the central tube, with a radial         deflection taking place at or adjacently to the central region;     -   an annular space is formed in the chamber around the central         tube;     -   the chamber has an inlet opening for an air-laden dirty fluid,         said inlet opening being formed on the central tube;     -   a ratio of an inner diameter of the central tube in the supply         of the air-laden dirty fluid to the rotor to an outer diameter         of the rotor is in the range between 0.1 and 0.5 and in         particular in the range between 0.25 and 0.35, and for example         is approximately 0.3.

The coaxial alignment of the central tube with the rotational axis results in a compact structure. The appropriate suction flow can be generated effectively. The air-laden dirty fluid can be effectively introduced into the chamber.

The directly opposite arrangement of the rotor relative to the central tube allows, on the one hand, effective application of negative pressure to the central tube to generate the suction flow. On the other hand, the air-laden dirty fluid can be effectively introduced into the rotor and a centrifugal separator can be effectively formed. The rotor can be in direct contact here with the central tube (for example by means of a labyrinth seal) or there can be a “smallish” gap, especially with a width of less than 1 mm, between the rotor and the central tube.

For the same reason, it is then favorable if the rotor has a central region and a radial deflection (and usually also a deflection in the peripheral direction) occurs at or adjacently to the central region.

It is very particularly advantageous if an annular space is formed in the chamber around the central tube. At suitable regions of the annular space, in which the quantity of liquid droplets is minimized, (dry) air can be separated in order to realize the liquid separator with the separation of air and liquid accordingly.

By means of the inlet opening for air-laden dirty fluid on the central tube, the air-laden dirty fluid is accordingly introduced into the chamber.

It has been shown that the above-mentioned ratio of the inner diameter of the central tube (corresponding to the central region of the rotor to which the air-laden dirty fluid is supplied by means of the central tube) and the outer diameter of the rotor results in an effective cleaning effect, especially for an extraction apparatus. Foam can be effectively broken down in the liquid separator. The cleaning result is optimized, for example, for spray extraction cleaning of textile materials, even if different volume flows are present. A high rotational speed of the rotor in the chamber can be achieved here, even with a compact construction of the suction cleaning apparatus.

It has proven to be advantageous if an air supply device is associated with the rotor, by means of which false air is suppliable to the rotor and, in particular, air is suppliable to a central region of the rotor from the chamber independently of a dirty fluid that has been sucked in. For example, when cleaning textile materials, the problem may arise that a suction opening on the acting device becomes blocked. Without the air supply device, this would result in an interruption of the volume flow. The air supply device allows false air to be introduced to the rotor by means of the central tube in order to maintain the volume flow. This results in improved operability and an improved cleaning results. A temporary blockage of a suction opening can be bridged.

In particular, at least one of the following is then provided:

-   -   the air supply device comprises one or more gaps between the         central tube and the rotor;     -   the air supply device comprises one or more openings of the         central tube to an interior of the chamber;     -   at least one false air valve is arranged on the central tube.

In each case, one of these measures, or a combination of two or more of these measures, allows air from the chamber to be introduced into the central tube to maintain a volume flow when needed.

A corresponding width of the at least one gap is greater than 0 mm and preferably less than 3 mm. For example, the width of this gap is in the range between 0.5 mm and 2 mm and particularly preferably approximately 1 mm.

If at least one false air valve is provided, it then opens in a defined manner when a certain pressure difference is present.

The at least one gap, the at least one opening or the at least one false air valve is directed in particular into a region of the chamber which contains a small amount of liquid during operation of the liquid separator.

For the removal of—dry—air from the chamber, it is advantageous if at least one dip tube is associated with the chamber, with at least one outlet opening for air being formed on the at least one dip tube. Air can be removed from the chamber by means of the at least one outlet opening for air. By providing at least one dip tube, the outlet opening of the at least one dip tube can be positioned in the chamber and, in particular, in an annular space around a central tube in such a way that the liquid impingement on the outlet opening is minimized.

In particular, at least one of the following is provided:

-   -   the at least one dip tube is oriented parallel or transverse to         the rotational axis;     -   the at least one dip tube is oriented parallel to and/or spaced         apart from a central tube by means of which an air-laden dirty         fluid is introduced into the chamber;     -   an end face of the at least one dip tube is spaced apart from an         end face of the central tube and/or is spaced apart from the         rotor;     -   the at least one dip tube has a smaller length than the central         tube (relative to the length within an interior of the chamber);     -   the at least one outlet opening for air is spaced apart from the         peripheral wall;     -   the at least one dip tube has circular-segment-shaped delimiting         walls adapted to the peripheral wall;     -   the at least one dip tube is positioned above the rotational         axis with respect to the direction of gravity during proper         operation of the suction cleaning apparatus;     -   the at least one dip tube has an extension in the form of a         collar at one end face, which extension is in particular         sharp-edged.

The measures mentioned allow effective—dry—air removal from the chamber. In particular, the at least one dip tube protrudes into a region in the chamber with favorable flow conditions, in which the liquid drop quantity is minimized.

A collar-shaped extension on the end face of the at least one dip tube, which is in particular sharp-edged and which is in particular formed in the manner of a disc, allows water droplets to drip off the collar and thus effectively prevents water droplets from penetrating the at least one dip tube.

In one exemplary embodiment the at least one dip tube is fluidically connected to the acting device and the acting device has at least one outlet opening for air. This allows air to be blown onto an area to be cleaned. This is advantageous, for example, in the event of flooding. As a result, liquid that has penetrated the at least one dip tube is then discharged back onto the area to be cleaned.

It is also possible that air provided by means of the at least one dip tube is not released to the environment by means of the acting device at another region of the suction cleaning apparatus.

In one embodiment, the chamber has a first end cover and has a second end cover between which the peripheral wall lies. The first end cover and the second end cover close an interior of the chamber.

In particular, at least one of the following is favorable:

-   -   the first end cover is positioned facing the acting device;     -   a central tube runs through the first end cover toward the rotor         or the central tube is seated on the first end cover;     -   at least one dip tube runs through the first end cover for         removing air from the chamber or the at least one dip tube is         seated on the first end cover;     -   the first end cover is oriented transversely and in particular         perpendicularly to the rotational axis.

The measures mentioned above result in a compact structure of the suction cleaning apparatus. The space required for the liquid separator can be minimized. The first end cover can be used to hold the central tube and/or the at least one dip tube. (For example, it is also possible in principle for the at least one dip tube to pass through the peripheral wall or to be held on the peripheral wall).

Furthermore, at least one of the following is favorable:

-   -   the rotor is adjacent to the second end cover and in particular         closer to the second end cover than to the first end cover;     -   with respect to an extension of the rotational axis, a drive         motor is arranged behind the second end cover and in particular         connected to the second end cover;     -   a rotary bearing for the rotor is arranged on the second end         cover;     -   the second end cover is oriented transversely and in particular         perpendicularly to the rotational axis.

The above-mentioned measures result in a compact structure of the suction cleaning apparatus. The space required for the corresponding components on the suction cleaning apparatus is minimized.

In accordance with an embodiment of the invention, a filter is arranged between the acting device and the liquid separator.

The corresponding suction cleaning apparatus can be effectively used to clean textile materials such as carpets. In particular, the suction cleaning apparatus is formed as an extraction apparatus as part of a spray extraction device.

The filter is formed in particular as a coarse dirt filter and in particular as a fluff filter. Fluff (lint) is constituted by fibers detached from textile material.

The upstream filter prevents coarse dirt from entering the chamber. This results in an effective mode of operation of the liquid separator.

In particular, the filter is arranged upstream of a chamber of the liquid separator. This prevents fluff from entering the liquid separator.

For the same reason, it is advantageous if, with respect to a flow direction of an air-laden dirty fluid, the filter is arranged upstream of a central tube by means of which the air-laden dirty fluid is introduced into a chamber.

In one embodiment, a flow path for an air-laden dirty fluid from the acting device to a chamber of the liquid separator has a deflection region, and the filter is arranged at the deflection region. This results in an optimized space utilization. The suction cleaning apparatus can be compact and formed, for example, as a hand-held or hand-guided apparatus. The result is an effective filtering of coarse dirt.

In one embodiment, the filter is arranged so to be removable from the suction cleaning apparatus and, in particular, can be removed from a housing outer side. An operator can then easily clean the fluff filter.

The filter, and in particular the fluff filter, is formed as a sieve, for example, which accordingly does not allow fluff of a typical size to pass through.

It is very particularly advantageous if, during operation of the suction cleaning apparatus, the rotor is operated at a rotational speed at which foam is broken down in the chamber.

Furthermore, it is advantageous if the suction cleaning apparatus is operated, with regard to the rotational speed of the rotor, in such a way that “automatic” cleaning of the rotor is performed, i.e. in such a way that dirt cannot settle on the rotor.

Depending on the particular application, it has proven to be advantageous if, during operation of the suction cleaning apparatus, the rotor has a rotational speed in the range between 1,000 revolutions per minute and 100,000 revolutions per minute, and in particular has a rotational speed in the range between 10,000 revolutions per minute and 50,000 revolutions per minute, and in particular has a rotational speed in the range between 25,000 revolutions per minute and 30,000 revolutions per minute. In particular, an extraction apparatus for cleaning textile materials can be effectively realized at a speed in the range between 25,000 revolutions per minute and 30,000 revolutions per minute.

It has also proven to be advantageous, particularly for cleaning textile materials, if an outer diameter of the rotor lies in the range between 20 mm and 150 mm, and in particular lies in the range between 40 mm and 80 mm, and in particular lies in the range between 66 mm and 70 mm.

It is very particularly advantageous if the at least one outlet opening for liquid is sharp-edged at least at a delimiting wall. This makes it possible to achieve an effective liquid droplet discharge into the holding tank for liquid.

In one exemplary embodiment, the at least one outlet opening for liquid is wedge-shaped with an acute wedge angle at least on one side, and in particular is sharply wedge-shaped on that side which faces a direction of rotation of the rotor. In this direction of rotation, liquid droplets are propelled toward the wedge-shaped side. Effective droplet removal into the holding tank for liquid can then be achieved.

Depending on the use of the suction cleaning apparatus, the acting device is formed differently. The acting device can comprise at least one of the following:

-   -   a wiper for liquid;     -   a cleaning roller, which is covered with a textile material, for         example;     -   a suction nozzle;     -   a dipping edge for a textile material;     -   at least one suction opening for an air-laden dirty fluid and at         least one channel, which leads to the liquid separator;     -   at least one outlet opening for air and at least one channel,         which leads to the liquid separator.

A wiper for liquid is used, for example, for a window cleaner. The wiper is used to apply the suction cleaning apparatus to the window surface to be cleaned.

A cleaning roller is used, for example, in a floor cleaning apparatus, which is hand-guided in particular by a standing operator. In this case, it is particularly provided that the cleaning roller is vacuumed off.

A (air-laden) dirty fluid can be sucked in accordingly by means of a suction nozzle.

The textile material can be combed to a certain extent by means of a dipping edge for a textile material in order to achieve an improved cleaning effect.

By means of the at least one suction opening, which is arranged for example on a wiper, above a cleaning roller, or integrated in a suction nozzle, the air-laden dirty fluid can be sucked in and supplied to the liquid separator via the at least one channel.

In one embodiment, in particular of an extraction apparatus for textile materials, at least one outlet opening for air is arranged on the acting device. This allows separate dry air to be blown out at the acting device onto the area to be cleaned. This can be advantageous, for example, in the event of flooding. Liquid that escapes in the event of flooding can thus be discharged onto the area to be cleaned.

It is advantageous if a battery device and in particular a rechargeable battery device (accumulator device) is provided for supplying electrical energy. This allows the suction cleaning apparatus to be operated autonomously. In principle, it is also possible for the suction cleaning apparatus to have a mains connection.

In one embodiment, a housing is provided which has a handle opening, the battery device being arranged on a web which delimits the handle opening and, in particular, delimits it toward a bottom side of the housing. This results in a compact embodiment with optimized use of space. Furthermore, an optimized operability can be achieved. The suction cleaning apparatus can be balanced to a certain extent, so that the effort required by an operator to hold the suction cleaning apparatus is minimized.

In one embodiment, a drive motor for the rotor follows the chamber and in particular directly follows the chamber, and the battery device follows the drive motor and in particular directly follows the drive motor. This allows these components to be accommodated in the housing in a space-saving manner. In this context, “directly” follows means that the components directly follow one another and, in particular, that a spacing between these components is at most 2 cm.

A compact structure is obtained if a housing with a bottom side is provided and the holding tank for liquid is seated removably on the bottom side. This results in an optimized use of space. Liquid from the liquid separator can be introduced into the holding tank in a simple manner. The holding tank for liquid can be realized with a large holding volume. A distance over which liquid must flow from the chamber of the liquid separator to the holding tank in order to be received by the latter can be minimized.

In one embodiment, the holding tank for liquid has a first region, a second region following the first region, and a third region following the second region, with liquid being introduced from the at least one outlet opening for liquid via the second region. In particular, a nozzle for coupling to the chamber of the liquid separator is seated on the second region. The holding tank for liquid can thus be optimally adapted to a housing shape of the suction cleaning apparatus and, on the one hand, there is an optimized discharge capability of (dirtied) liquid from the chamber to the holding tank and, on the other hand, the holding tank can be realized with a high holding volume for liquid.

In particular, it is then favorable if the first region and the third region each have a greater height than the second region, and in particular if the cross-section of the holding tank for liquid is C-shaped or U-shaped.

The third region is positioned advantageously opposite a drive motor when the suction cleaning apparatus is fitted with a holding tank for liquid. The first region is positioned facing the acting device.

The suction cleaning apparatus is formed in particular as a hand-held or hand-guided suction cleaning apparatus. The form according to the invention allows the suction cleaning apparatus to be formed in a compact manner, so that it can be used as a hand-held or hand-guided device, correspondingly. For example, furniture comprising textile materials, such as car seats, can be cleaned effectively. For example, backrests and the like can also be cleaned effectively.

In one embodiment, the suction cleaning apparatus is formed as an extraction apparatus or spray extraction apparatus for textile materials, which is particularly hand-held. In a spray extraction apparatus for textile materials, a cleaning liquid (usually water with a surfactant-based cleaning agent additive) is sprayed onto the textile material. The corresponding dirty fluid is then extracted by means of the extraction apparatus. The dirty fluid is air-laden and the air-liquid separation then takes place by means of the liquid separator. The suction cleaning apparatus can comprise here the spray device for spraying the textile material or can be a separate part of a spray extraction device, namely the part by means of which the extraction (the removal of the dirty fluid by extraction) takes place.

According to an embodiment of the invention, a method is provided for operating a suction cleaning apparatus and in particular a suction cleaning apparatus according to the invention, in which a negative pressure is generated by a rotor of a liquid separator, by means of which an air-laden dirty fluid is sucked into a chamber of the liquid separator, and in which the liquid separator acts as a centrifugal separator via the rotating rotor, with separated liquid being discharged to a holding tank for liquid by means of at least one outlet opening for liquid, which is arranged on a peripheral wall of the chamber.

The method in accordance with the invention has the advantages already explained in conjunction with the suction cleaning apparatus according to the invention. In particular, the suction cleaning apparatus according to the invention can be operated with the method according to the invention, or the method according to the invention can be carried out on the suction cleaning apparatus according to the invention.

It is very particularly advantageous if an air-laden dirty fluid sucked in is passed through a filter such as a fluff filter before entering the liquid separator. This is a particularly effective way of cleaning textile materials such as carpets or upholstery. The penetration of coarse dirt such as fluff into the chamber of the liquid separator is prevented.

It is also advantageous if dry air is discharged from the chamber by means of at least one dip tube, wherein in particular the at least one dip tube protrudes into a region of the chamber with favorable flow conditions, where a small amount of liquid is present.

The following description of preferred embodiments in conjunction with the drawings serves to explain the invention in greater detail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective illustration of an exemplary embodiment of a suction cleaning apparatus according to the invention;

FIG. 2 shows a side view of the suction cleaning apparatus according to FIG. 1 ;

FIG. 3 shows a sectional view of the suction cleaning apparatus according to FIG. 1 ;

FIG. 4 shows an enlarged view of the region A according to FIG. 3 ;

FIG. 5 shows a sectional view along the line 5-5 according to FIG. 2 ;

FIG. 6 shows a sectional view along the line 6-6 according to FIG. 2 ;

FIG. 7 shows a partial illustration of the suction cleaning apparatus according to FIG. 1 in the sectional view according to FIG. 3 with an acting device, a liquid separator and a holding tank for liquid;

FIG. 8 shows a front view of the liquid separator according to FIG. 7 in direction B according to FIG. 7 ;

FIG. 9 shows a view of the liquid separator according to FIG. 8 in direction C according to FIG. 8 ;

FIG. 10 shows a side view of the liquid separator according to FIG. 8 in direction D according to FIG. 8 ;

FIG. 11 shows a partial sectional view of the liquid separator according to FIG. 8 along line 11-11;

FIG. 12 shows another exemplary embodiment of a liquid separator in a sectional illustration similar to the sectional illustration of FIG. 11 ;

FIG. 13 shows a sectional view of a further exemplary embodiment of a liquid separator;

FIG. 14 shows a sectional view similar to the sectional view according to FIG. 5 for a further exemplary embodiment of a liquid separator;

FIG. 15 shows a sectional view of a further exemplary embodiment of a liquid separator similar to the view according to FIG. 12 ;

FIG. 16 shows a second exemplary embodiment of a suction cleaning apparatus according to the invention; and

FIG. 17 shows a third exemplary embodiment of a suction cleaning apparatus according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

A first exemplary embodiment of a suction cleaning apparatus 10 according to the invention (FIGS. 1 to 15 ) is an extraction apparatus for cleaning textile materials and, in particular, textile coverings such as carpets.

Usually, for this purpose a cleaning liquid is sprayed onto the textile material. The cleaning liquid is in particular a mixture here of water with an addition of, for example, a surfactant-based cleaning agent.

The suction cleaning apparatus 10 may be a spray extraction apparatus, in which a spray device is arranged on the suction cleaning apparatus (not shown in the drawings).

It is also possible that the cleaning liquid is sprayed separately from the suction cleaning apparatus 10 onto the textile surface to be cleaned.

The suction cleaning device 10 comprises a housing 12. A housing interior 14 is formed in the housing 12 and has functional components of the suction cleaning device 10.

The housing 12 has a first housing wall 16 and an opposite second housing wall 18 (FIGS. 1 and 2 ). The first housing wall 16 and the second housing wall 18 are connected to each other by means of a first intermediate wall 20 and a second intermediate wall 22.

The housing 12 has a top side 24. This top side 24 is formed on the first intermediate wall 20.

The housing 12 has a front side 26, which is also formed on the first intermediate wall 20. The front side 26 lies at an obtuse angle, which is in the order of 110° for example, to the top side 24.

The housing 12 further has a bottom side 28 that is opposite the top side 24. The bottom side 28 is formed on the second intermediate wall 22.

Furthermore, the housing 12 has a rear side 30 that faces away from the front side 26.

A handle 32 is formed on the housing 12 for holding the suction cleaning apparatus 10. This allows hand-held operation of the suction cleaning apparatus 10. In particular, an operator can hold the suction cleaning apparatus 10 with a single hand.

A handle opening 34 is provided on the housing 12. The handle opening 34 is a continuous opening through the first housing wall 16 and the second housing wall 18. The handle opening 34 is delimited toward the top side 24 of the housing 12 by a first web 36 of the housing 12. Toward the bottom side 28, the handle opening is delimited by a second web 38 of the housing 12. Toward the rear side 30, the first web 36 and the second web 38 are connected by a third web 40. This third web 40 delimits the handle opening 34 toward the rear side 30.

Furthermore, between the first web 36 and the second web 38 toward the front side 26 there is a wall 42 that delimits the handle opening 34.

The first web 36, the second web 38 and the third web 40 are closed outwardly by corresponding walls.

An operator can hold the suction cleaning apparatus 10 with one hand at the first web 36. In doing so, they can pass the holding fingers (in particular the fingers of the corresponding holding hand without thumb) through the handle opening 34.

A switch 44 is arranged on the first intermediate wall 20 (on the top side 24). This switch is arranged in particular in relation to the handle 32 in such a way that an operator who holds the suction cleaning apparatus 10 on the handle 32 with a holding hand can operate the switch 44, for example, by means of the thumb of the holding hand. The switch 44 is used in particular to activate or deactivate a suction function of the suction cleaning apparatus 10.

It may be provided that a spray device (for cleaning liquid) is also activated or deactivated by means of the switch 44, wherein, as described above, the spray device can be arranged on the suction cleaning apparatus 10 (not shown in the drawings), or may be separate therefrom.

In the case of a separate spray device, for example, the switch 44 can be used to wirelessly activate or deactivate the spray device.

A removable holding tank 46 for liquid is positioned on the housing 12.

In the exemplary embodiment shown, the holding tank 46 is seated on the bottom side 28 of the housing 12.

The holding tank 46 can be removed from the housing 12 in a direction 48 corresponding to a direction from the top side 24 to the bottom side 28. Accordingly, the holding tank 46 can be inserted into the housing 12 in the opposite direction to the direction 48.

The holding tank 46 is releasably fixable to the housing 12 by means of a fixing device.

The suction cleaning apparatus 10 comprises a suction unit device 50, which is arranged in the housing interior 14. The suction unit device 50 generates a negative pressure, by which a suction flow can be generated. During the cleaning action on an area 51 to be cleaned (FIG. 3 ), a dirty fluid, which is air-laden, is sucked in during operation of the suction cleaning apparatus 10. The dirty fluid contains cleaning liquid and dirt, which in particular is at least partially dissolved in the cleaning liquid. (The term “dirty fluid” is understood here also to mean a sucked-in liquid which is not dirt-laden, for example because the area 51 to be cleaned is dirt-free).

A liquid separator 52 is provided to separate air and liquid from the air-laden dirty fluid.

The suction unit device 50 and the liquid separator 52 are integrally formed, i.e., the liquid separator 52 acts as the suction unit device 50 (and generates a negative pressure for sucking in the air-laden dirty fluid) or the suction unit device 50 acts as the liquid separator 52 (and separates liquid from air).

The liquid separator 52 or the suction unit device 50 comprises a chamber 54 positioned in the housing interior 14. The chamber 54 has a peripheral wall 56. A chamber interior 58 is laterally closed by the peripheral wall 56. At the end faces, the chamber interior 58 is closed by a first end cover 60 and an opposite, second end cover 62, the peripheral wall 56 lying between the first end cover 60 and the second end cover 62 and being connected to each of them.

The chamber 54 has an axis 64 oriented in an axial direction.

For the most part, the chamber 54 is rotationally symmetrical about this axis 64.

In one exemplary embodiment (FIGS. 3 and 5 to 11 ), the chamber 54 is cylindrical. The peripheral wall 56 is parallel to the axis 64.

In particular, the first end cover 60 and the second end cover 62 are oriented parallel to each other and transversely and preferably perpendicularly to the axis 64.

A rotor 66 is rotatably positioned in the chamber interior 58. The rotor 66 is rotatably mounted about a rotational axis 70 by means of a rotary bearing 68.

In one exemplary embodiment (FIG. 3 ), the rotary bearing 68 is arranged on the second end cover 62.

The rotational axis 70 is coaxial with the axis 64.

Correspondingly, the rotational axis 70 is then oriented parallel to the peripheral wall 56 or transversely and in particular perpendicularly to the first end cover 60 and to the second end cover 62.

A drive motor 72 is provided to drive the rotational movement of the rotor 66. This drive motor 72 is in particular an electric motor.

The drive motor 72 is positioned outside the chamber 54. In particular, it is arranged in a motor housing 74, which is arranged in the housing interior 14 behind the chamber 54. For example, the motor housing 74 is fixed to the second end cover 62.

It is provided in the embodiment shown that the drive motor 72 directly drives the rotor 66 (without an intermediate transmission).

In particular, it is provided that the drive motor 72 immediately follows the rotor 66, that is to say, is arranged directly behind the rotor 66.

In this context, “immediately” or “directly” means that a spacing between the rotary bearing 68 and the drive motor 72 is at most 2 cm.

The drive motor 72 is supplied with electrical energy by means of a battery device 76 and, in particular, a rechargeable battery device 76. The battery device 76 is arranged in the second web 38.

The battery device 76 follows immediately or directly after the drive motor 72. The term “immediately” or “directly” is understood here to mean that a spacing between the motor housing 74 and the battery device 76 is at most 2 cm.

A central tube 78 is arranged on the chamber 54, or the chamber 54 comprises the central tube 78. The central tube 78 is guided through the first end cover 60 or is seated on the first end cover 60. The air-laden dirty fluid can be introduced into the chamber interior 58 by means of the central tube 78.

The central tube 78 is arranged coaxially with the axis 64 and thus also coaxially with the rotational axis 70. The central tube has an interior 80, which is in particular hollow-cylindrical.

The central tube 78 extends to the rotor 66. In particular, the rotor 66 contacts the central tube 78 by means of a region 82. For example, a labyrinth seal is seated at the region 82.

It is also possible that a “smallish” gap, in particular with a width of less than 1 mm, is located between the rotor 66 and the central tube 88.

In one exemplary embodiment, the central tube 78 is provided with a collar 84 at the end, with the region 82 being formed at said collar.

For example, the rotor 66 has an annular web 86 which faces the central tube 78 and which is dipped into a corresponding annular recess on the collar 84.

The dirty fluid is introduced by means of the central tube 78 in a main flow direction 88, which is axially oriented.

At the rotor 66, the flow is deflected in the radial direction (indicated in FIG. 3 by double-lined arrows with reference sign 90) and in the peripheral direction, relative to the axial direction of the axis 64.

The rotor 66 is spaced apart from the first end cover 60 in the chamber interior 58. It is closer to the second end cover 62 than to the first end cover 60. It is provided with blades 92 (FIGS. 5 and 6 ) which are arranged at an angle to the radial direction.

In the rotor 66 shown in FIGS. 5 and 6 with the blades 92, these blades 92 are straight.

In principle, it is also possible for the blades 92 to be formed in a curved shape.

The rotor 66 generates the necessary negative pressure for the suction flow, that is to say for sucking in the air-laden suction fluid. In particular, the rotor 66 is formed as an impeller.

The rotor 66 is furthermore part of the liquid separator 52. Liquid droplets are propelled outwardly toward the peripheral wall 56 by means of the rotor 66.

At least one outlet opening 94 for liquid is arranged on the peripheral wall 56. Dirt-laden liquid, which is “deaerated”, can be discharged through this at least one outlet opening 94 for liquid (compare also FIGS. 5 and 6 ).

The at least one outlet opening 94 is a type of disruption in the rotational symmetry of the peripheral wall 56 with respect to the axis 64.

The chamber 54 has a height H (FIG. 3 ) in a height direction parallel to the axis 64.

In an exemplary embodiment, the outlet opening 94 extends over at least 50% and preferably over at least 70% and preferably over at least 80% of this height H of the chamber 54 in the chamber interior 58 (compare FIG. 9 ).

The at least one outlet opening can be a plurality of individual openings or exactly one outlet opening (compare FIG. 9 ).

In particular, exactly one outlet opening 94 for liquid is provided, which is in the form of a slot.

The liquid separator 52 is formed as a centrifugal separator. Liquid droplets are propelled outwardly and discharged by means of the outlet opening 94 at the peripheral edge of the chamber 54.

In the suction cleaning apparatus 10, which is formed as a hand-held apparatus, the at least one outlet opening 94 is positioned geometrically below the rotational axis 70 or geometrically below the axis 64 with respect to the direction of gravity g, based on a proper operating mode for cleaning a surface that is horizontal with respect to the direction of gravity g (compare FIG. 3 ), in which the suction cleaning apparatus 10 is held at the handle 32 and acts on the area 51 to be cleaned by means of a acting device 96. In this case, the handle 32 is oriented above the area 51 to be cleaned with respect to the direction of gravity g.

Such an operation is then performed in particular when the suction cleaning apparatus 10 is used for cleaning a floor or a seating surface made of textile material.

The suction cleaning apparatus 10 can also be used to clean vertical surfaces or inclined surfaces such as backrests made of textile material.

Other arrangements of the at least one outlet opening are also possible. For example, a plurality of outlet openings are provided, with all outlet openings then being arranged accordingly, or only some of the outlet openings being arranged accordingly, or no outlet opening being arranged as described.

The at least one outlet opening 94 opens out into the holding tank 46 for liquid. Accordingly, the latter has an inlet opening 98 which corresponds to the at least one outlet opening 94 when the holding tank 46 is arranged on the housing 12.

In particular, by means of the at least one outlet opening 94 for liquid, dirty liquid is propelled directly into the holding tank 46 for liquid via the inlet opening 98.

A mouth normal of the at least one outlet opening 94 is oriented transversely and, in particular, perpendicularly to the rotational axis 70.

The at least one outlet opening 94 is delimited by a delimiting wall 100 (FIGS. 5 and 6 ). The delimiting wall 100 is part of the peripheral wall 56; the one outlet opening 94 is a continuous cut-out on the peripheral wall 56.

The at least one outlet opening 94 is formed with a sharp edge on at least one side by way of an appropriate form of the delimiting wall 100. This improves the introduction of liquid into the holding tank 46 for liquid.

In one embodiment, the delimiting wall 100 is formed as a wedge element 102 on one side. In this region, the delimiting wall 100 is wedge-shaped and has a wedge tip 104, which is sharp-edged correspondingly. A wedge angle at the wedge tip 104 is an acute angle.

In the exemplary embodiment shown, this wedge angle is in the order of 40°.

The wedge element 102 faces a direction of rotation 106 (FIGS. 5 and 6 ) of the rotor 66. Thus, an improved liquid discharge is achieved.

In one embodiment, the chamber 54 has a connection piece 108 in the region of the at least one outlet opening 94. The holding tank 46 can be fitted onto this connection piece 108.

The holding tank 46 for liquid comprises a bottom wall 110, a side wall 112, and a cover wall 114 (FIGS. 1 to 6 ).

By means of the cover wall 114 and the side wall 112, the holding tank 46, when fixed to the housing 12, is placed against the bottom side 28 of the housing 12.

A counter element 116 for the connection piece 108 is arranged on the cover wall 114. The cover wall 114 and thus the holding tank 46 can be fitted onto the connection piece 108 by means of the counter element 116.

The holding tank 46 extends in a longitudinal direction 118 (FIG. 7 ), which (when the holding tank 46 is seated on the housing 12) is at least approximately parallel to the axis 64 or the rotational axis 70 (FIG. 7 ).

With respect to the longitudinal direction 118, the holding tank 46 has a first region 120, a second region 122 following the first region, and a third region 124 following the second region.

A height H₁ of the first region 120 in a height direction perpendicular to the longitudinal direction 118 is higher than a height H₂ of the second region 122. A height H₃ of the third region 124 is also higher than the height H₂ of the second region 122.

The counter element 116 is seated at the second region 122.

The first region 120 faces the acting device 96.

The third region 124 faces the drive motor 72.

In a cross-section (containing the connection piece 108) shown in FIG. 7 and which is parallel to the rotational axis 70, the holding tank 46 has at least approximately a C-shaped or U-shaped form.

Because of the counter element 116, which is configured to be fitted onto the connection piece 108, the holding tank 46 also has a C-shaped or U-shaped form in a cross-section perpendicular to the rotational axis 70 containing the connection piece 108 (FIGS. 5 and 6 ).

Due to the described form of the holding tank 46 for liquid, it can be optimally positioned on the housing 12. This results in an optimized use of space for the suction cleaning apparatus 10, especially if hand-held operation is intended. A relatively high holding volume can be provided for the holding tank 46.

In the liquid separator 52, air from the air-laden dirty fluid is separated from liquid. An annular space 126 is formed around the central tube 78 in the chamber interior 58 of the chamber 54.

The chamber 54 has at least one dip tube 128 protruding into the annular space 126. The dip tube is arranged on the first end cover 60 of the chamber 54 and/or extends through this first end cover 60.

The at least one dip tube 128 comprises an outlet opening 130 (FIG. 7 ) for air, by means of which (dry) air can be discharged from the chamber interior 58.

In one embodiment, the outlet opening 130 is spaced apart here from the peripheral wall 56, spaced apart from the central tube 78, and spaced apart from the rotor 66.

In the exemplary embodiment shown in FIG. 7 , the dip tube 128 is oriented parallel to the axis 64 or to the rotational axis 70.

The dip tube 128 is arranged and formed in such a way that it is positioned with respect to its outlet opening 130 in a region within the annular space 126 with particularly favorable flow conditions. In this region with favorable flow conditions, the amount of liquid is small.

In the exemplary embodiment according to FIG. 7 , the outlet opening 130 is directed into a region of the annular space 126 which lies beyond the rotational axis 70 with respect to the at least one outlet opening 94. The rotational axis 70 thus lies between the dip tube 128 and the outlet opening 94 for liquid.

In proper operation of the suction cleaning apparatus 10 for cleaning a horizontal surface, in which the outlet opening 94 for liquid is geometrically below the rotational axis 70 with respect to the direction of gravity g, the dip tube 128 is positioned geometrically above the rotational axis 70 with respect to the direction of gravity g.

Other operating modes such as cleaning a vertical surface or an inclined surface are also possible.

A collar 134 is arranged on an end face 132 of the dip tube 128. The collar 134 represents a flange-like or disc-shaped extension of the dip tube 128 at the end face 132.

In particular, the collar 134 is sharp-edged at its periphery. As a result, liquid droplets can drip off from the collar 134 due to the air flow and cannot enter the dip tube 128.

The suction cleaning apparatus 10 has an air discharge device 136, by means of which separated—dry—air provided by the liquid separator 52 by means of the at least one dip tube 128 is released to the environment.

In one exemplary embodiment (FIG. 6 ), the (at least one) dip tube 128 has circular-segment-shaped delimiting walls 138. An inner delimiting wall 138 a and an outer delimiting wall 138 b are provided (FIG. 6 ). The course of these follows the peripheral wall 56, that is to say they are oriented in particular in parallel and extend over a circular segment, for example in an angular range of approximately 60°.

The inner delimiting wall 138 a and the outer delimiting wall 138 b are connected to one another by respective rounded walls.

The suction cleaning apparatus 10 acts by means of the acting device 96 on the area 51 to be cleaned. In an extraction apparatus, the area 51 to be cleaned is a textile surface.

The acting device 96 comprises a dipping edge 140 (FIG. 4 ), which can be dipped into the textile material in order to comb through it.

The dipping edge 140 is located here on the front side 26.

The acting device 96 further comprises a suction opening 142 through which the air-laden dirty fluid can be sucked in. The suction opening 142 is fluidically connected to the central tube 78; (at least) one channel 144 leads from the suction opening 142 to the central tube 78. The air-laden dirty fluid is conveyed through this channel 144 into the liquid separator 52.

The suction cleaning apparatus 10 has a filter 146. This filter 146 is in particular a coarse dirty filter. In an extraction apparatus for textile materials, the filter is in particular a fluff filter and serves to filter out fluff (lint) which is sucked in during the cleaning of a textile material and prevents fluff from entering the chamber 54. Fluff is constituted by loosened textile fibers.

The filter 146 is formed in particular by a screen made, for example, of a metal material or plastics material.

Accordingly, the filter 146 is arranged upstream of the liquid separator 52 with the central tube 78.

The exemplary embodiment of the suction cleaning apparatus 10 comprises a deflection region 148 (FIG. 3 ), at which the air-laden flow fluid undergoes a directional deflection. This deflection region 148 lies at the end of the channel 144 and at the start of the central tube 78.

The filter 146 is arranged in this deflection region 148. A flow inlet of the filter 146 is (directly) connected to the end of the channel 144. A flow outlet of the filter 146 is (directly) connected to the central tube 78. With regard to coarse dirt, here the flow inlet represents a dirty side and the flow outlet a clean side.

The filter 146 is held on the housing 12 by a filter holder 150.

In particular, the filter is removable from the housing 12, moreover removable outwards.

In one exemplary embodiment, the filter 146 is arranged in the region of the first intermediate wall 20, moreover on the front side 26.

The filter can be removed outwards to the front (compare FIG. 1 ). In FIG. 1 , a removal direction is indicated by the reference sign 152.

For example, the filter holder 150 is provided with a handle element 154 that allows an operator to insert or remove the filter 146 into/from a corresponding recess on the housing 12 (on the front side 26).

By providing the filter 146, the suction cleaning apparatus 10 is optimized for the cleaning of textile materials. Coarse dirt such as fluff cannot enter the liquid separator 52.

In one embodiment, the filter 146 is made to be washable and thus reusable.

In one embodiment (compare FIG. 4 ), an outlet opening 156 for air is arranged next to the suction opening 142. This outlet opening 156 is fluidically connected to the at least one dip tube 128 by means of at least one channel 158. Separated—dry—air can thus be removed from the suction cleaning apparatus 10. The outlet opening with the channel 158 forms the air discharge device 136, which is connected to the dip tube 128.

Dry air is then delivered to the area 51 to be cleaned.

In principle, it is also possible for dry air to be released from the liquid separator 52 to the environment, for example via the first intermediate wall 20.

The suction cleaning apparatus 10 in its form as an extraction apparatus in conjunction with a spray device functions as follows:

The area 51 to be cleaned, i.e. the area made of textile material, is sprayed with a cleaning agent. The cleaning agent is preferably water containing, for example, a surfactant-based cleaning additive.

The corresponding damp surface is processed with the hand-held suction cleaning apparatus 10. An operator holds the suction cleaning apparatus 10 by the handle 32 in such a way that the dipping edge 140 penetrates the textile material. The operator then moves the suction cleaning apparatus 10 over the area 51 to be cleaned and combs through it to a certain extent.

Horizontal surfaces, vertical surfaces and inclined surfaces can be cleaned. In particular, upholstered backrests can also be cleaned. The apparatus can also be used in confined spaces, such as in a vehicle.

During operation of the suction cleaning apparatus 10, the rotor 66 rotates in the chamber 54. A negative pressure is thus created. The suction fluid is thus sucked in at the suction opening 142 from the area to be cleaned. The suction fluid is air-laden. It flows in the channel 144 to the central tube 78.

The air-laden dirty fluid, which is in particular a (at least) two-phase mixture of air and liquid, is indicated in the drawings by a double-lined arrow 160 (compare FIG. 4 ).

The air-laden dirt flows through the filter 146, where in particular fluff is filtered out.

It flows via the central tube 78 to the rotor 66 and from there to a central region. A flow deflection takes place (compare, for example, FIG. 3 ), and then a flow with a radial directional component (and also a peripheral directional component) occurs due to the arrangement of the blades 92.

The liquid separator 52 is formed as a centrifugal separator. Due to the centrifugal force, liquid droplets are propelled outwards to the peripheral wall 56.

The outlet opening 94 for liquid is located there.

This allows dirt-laden liquid having a low air content to be discharged and introduced into the holding tank 46 for liquid.

In addition, an introduction of (dirtied) liquid, which is indicated by a wavy arrow 162 (compare, for example, FIG. 5 ), can be conveyed here into the holding tank 46 in a gravity-driven manner.

In particular, droplets of liquid can pass along the peripheral wall to the outlet opening 94.

The outlet opening 94 is sharp-edged, in particular with the wedge element 102. This results in an optimized discharge.

The at least one dip tube 128 protrudes into a region of the annular space 126 around the central tube 78 in which the amount of liquid is small.

Dry air can be discharged by means of the at least one dip tube 128.

In the exemplary embodiment shown, the air discharge device 136 leads to the outlet opening 156, which is adjacent to the suction opening 142.

Dirtied liquid accumulates in the holding tank 46.

The holding tank 46 is removable from the housing 12 for emptying and cleaning.

In particular, the suction cleaning apparatus 10 is battery-powered by means of the battery device 76. For example, the battery device 76 is an accumulator device.

When operating a suction cleaning apparatus 10 for cleaning textile materials, a high level of foam development can generally occur due to the intake of air and possibly also due to the addition of a cleaning agent, for example a surfactant-based cleaning agent. Furthermore, the volume flows with regard to the dirty fluid can be very different.

Furthermore, due to the relatively small suction opening, a large negative pressure can prevail in a small space.

The liquid separator 52 is formed so as to break down a foam within the chamber 54. Largely droplet-free air is blown out through the dip tube 128 at the outlet opening 156. Dirtied liquid is ejected from the chamber 54 into the holding tank 46 for liquid through the at least one outlet opening 94, which is in particular formed as a slot.

In operation of the suction cleaning apparatus 10, a rotational speed of the rotor 66 is in the range between 1,000 revolutions per minute and 100,000 revolutions per minute, preferably in the range between 10,000 revolutions per minute and 50,000 revolutions per minute, and very particularly preferably in the range between 25,000 revolutions per minute and 30,000 revolutions per minute.

An outer diameter D of the rotor 66 (compare FIG. 6 ) is preferably in the range between 20 mm and 150 mm, particularly preferably in the range between 40 mm and 80 mm, and particularly preferably in the range between 66 mm and 70 mm. In a specific exemplary embodiment, the outer diameter D is 68 mm.

An inlet diameter E for the entry of the dirty fluid into the chamber 54 at the rotor 66 is defined by the central tube 66.

The ratio of this inlet diameter E to the outer diameter D* of the rotor 66 is in particular in the range between 0.1 and 0.5. In a specific exemplary embodiment, this ratio E to D* is approximately 0.3.

During a cleaning process, for example with a dense textile material, the problem may basically arise that the suction opening 142 is closed and the volume flow is interrupted as a result.

According to the invention, in order to avoid such a problem, an air supply device 164 (compare FIG. 11 ) is provided, through which false air is supplied to the central tube 70 from the chamber interior 58.

False air is then supplied to rotor 66 accordingly.

In one exemplary embodiment, the air supply device 164 comprises a gap 166 (FIG. 11 ) located between the central tube 78 and the rotor 66 at the end face of the central tube 78.

This gap 166 provides a fluid connection between an interior of the central tube 78 and the chamber interior 58.

A width B* (compare FIG. 11 ) of this gap 166, which provides corresponding false air, is in particular greater than 0 mm and goes up to 3 mm. Preferably, the width B* is in the range between 0.5 mm and 2 mm.

The air supply device for supplying false air to the rotor 66 may alternatively or additionally have one or more openings 168 on the central tube 78 toward the chamber interior 58.

Alternatively or additionally, it is also possible that one or more false air valves are arranged on the central tube 78, through which defined false air can be introduced into the flow path to the rotor 66.

In FIG. 11 , a false air flow is indicated by arrows 170 with broken lines.

A flow of dry air is indicated in the drawings by a solid single-lined arrow 172.

The suction cleaning apparatus 10 is compact. This results in an optimized use of space. The suction unit device 50 and the liquid separator 52 are integrated. The suction unit 50 is a centrifugal separator and the liquid separator 52 comprises a blower for generating negative pressure.

The battery device 76 is arranged in the second web 38.

For example, a control device 174 (FIG. 3 ) is arranged in the first web 36.

In particular, one-handed operation of the suction cleaning apparatus 10 is also possible. An operator holds the suction cleaning apparatus 10 with one hand at the handle 32, the apparatus being supported by means of the acting device 96 at the area 51 to be cleaned.

For example, an operator can then operate a spray device with the other hand.

Even if the sucked-in air-laden suction fluid foams heavily, foam can be broken down by means of the rotor 66. The suction cleaning unit 10 can also be used with very different volume flows. A compact construction can be achieved, so that a hand-held apparatus is also realizable.

The fluff filter 146 prevents fluff from entering the chamber interior 58 and impairing its function.

There is a separate air path for dry air, said air path being connected to the at least one dip tube 128. There is also a separate liquid path for separated liquid, said liquid path being connected to the outlet opening 94.

The rotor 66 rotates at a relatively high speed during operation. As a result, dirt is thrown off and the rotor 66 remains “clean”.

In the exemplary embodiment of the suction cleaning apparatus 10, dry air is blown onto the area to be cleaned. This results in a compact structure. The noise emission of the suction cleaning apparatus 10 is kept low.

If flooding occurs at the liquid separator 52, liquid from the dip tube 128 is reapplied to the area to be cleaned, resulting in optimized manageability.

In one embodiment, in particular as an extraction apparatus, the suction cleaning apparatus 10 has a power consumption in the order of 90 W.

Another exemplary embodiment of a liquid separator 176, which is shown in a sectional illustration in FIG. 12 , comprises a chamber 178 having a peripheral wall 180.

The chamber 178 is frustoconical. The peripheral wall 180 is inclined relative to an axis 182 which is coaxial with a rotational axis.

An imaginary tip of the truncated cone lies in this case away from a central tube 184.

In the peripheral wall 180 there is formed (at least) one outlet opening 184 for liquid. This leads to a holding tank for liquid corresponding to the holding tank 46.

The chamber 178 is formed with the peripheral wall 180 rotationally symmetrical to the axis 182 (except for the outlet opening 184).

In particular, with regard to an operating mode for cleaning of a surface that is horizontal with respect to the direction of gravity g, the outlet opening 184, with preferably a single outlet opening 184 being provided, with respect to the axis 182 and correspondingly the rotational axis lies geometrically below this axis 182 (with respect to the direction of gravity g), as described above in conjunction with the suction cleaning apparatus 10.

By means of the peripheral wall arranged at an angle of the axis 182, a supply region 186 in the manner of an inclined plane is formed toward the outlet opening 184 by the peripheral wall 180. This supply region extends in particular over at least 80% of an inner height of the chamber 178 parallel to the axis 182.

A type of funnel is formed over the supply region 186, and liquid can then be discharged through the outlet opening 184.

At the supply region 186, gravity-driven liquid can flow to the outlet opening 184.

Otherwise, the liquid separator 176 functions as described above with reference to the liquid separator 52.

In another exemplary embodiment of a liquid separator, shown in a sectional drawing in FIG. 13 and denoted by 188, a chamber 190 with a peripheral wall 192 is provided. The chamber 190 is rotationally symmetrical about an axis 194, which is coaxial with a rotational axis of a rotor arranged in the chamber 190.

The chamber 190 has the shape of a combination of two truncated cones, with imaginary cone tips lying on the axis 194 on either side of the chamber 190.

The peripheral wall 192 has a first region 196 and a second region 198. These are inclined relative to the axis 194 at the same angle, but with a different sign, and meet each other in a region of maximum diameter of the chamber 190.

At the peripheral wall 192 there is formed (at least) one outlet opening 200 for liquid. Based on proper operation, this outlet opening 200 lies below the axis 194, in particular with respect to the direction of gravity.

The outlet opening 200 is located at a transition from the first region 196 to the second region 198.

A supply region 202 for liquid to the outlet opening 200 is thus formed and comprises a first inclined region 204 and a second inclined region 206. A funnel is thus formed and liquid can then flow, driven by gravity, along the first inclined region 204 and the second inclined region 206 to the outlet opening 200. The outlet opening 200 represents a type of collection region.

Otherwise, the liquid separator 188 is formed in the same way as the liquid separator 52 and functions in the same manner.

In a further exemplary embodiment of a liquid separator, which is shown schematically in a sectional view in FIG. 14 and is denoted by 208, a chamber 210 is provided. A dip tube 212 for discharging (dry) air opens out into the chamber 210.

The dip tube 212 is oriented here transversely and, for example, perpendicularly to an axis 214 of the chamber 210, the axis 214 being coaxial with a corresponding rotational axis of a rotor arranged in the chamber 210.

Air is then discharged transversely to the axis 214 by means of the dip tube 212.

In particular, it is provided here that the dip tube 212 opens out into a region inside the chamber 210 in which a minimal amount of liquid droplets are present.

Otherwise, the liquid separator 208 functions as described above with reference to the liquid separator 52.

Another exemplary embodiment of a liquid separator 216, shown in a sectional illustration in FIG. 15 , comprises a chamber 218. A plurality of dip tubes 220, 222 for discharging (dry) air open out into said chamber.

In the embodiment shown, the dip tubes 220, 222 are oriented parallel to each other and parallel to a central tube 224. In particular, the central tube 224 lies between the dip tube 220 and the dip tube 222.

Dry air can thus be discharged from the chamber 218 at multiple locations (that is to say, at least at two locations).

Otherwise, the liquid separator 216 functions as described above with reference to the liquid separator 52.

Components of the liquid separators 176 and/or 188 and/or 208 and/or 216 can also be combined with each other. For example, a funnel-shaped form of the peripheral wall 180 or 192, as described with reference to the liquid separators 176 and 188, can also be combined with a transversely arranged dip tube 212, as described with reference to the liquid separator 208, or with a plurality of dip tubes 220, 222, as described with reference to the liquid separator 216.

For example, a plurality of transversely arranged dip tubes 212 may also be provided.

A liquid separator 52 with integrated suction unit device 50 and, in particular, with a rotor 66 formed as an impeller and, preferably, at least one outlet opening 94 for liquid, which is arranged on a peripheral wall 56, can also be used in suction cleaning apparatuses other than an extraction apparatus.

FIG. 16 shows a window cleaner 226 as a second exemplary embodiment of a suction apparatus according to the invention. This window cleaner has a wiper 230 as an acting device, which comprises spaced-apart lips. A suction opening 232 is formed between the lips.

This suction opening 232 is fluidically connected to a liquid separator according to the invention, such as the liquid separator 52.

In a cleaning mode of the window cleaner 226, the wiper 230 is used to wipe a dirty fluid from a window to be cleaned, sucking the dirty fluid in during this process.

The dirty fluid sucked in is air-laden.

In the liquid separator 52, a separation of dirtied liquid and a separation of dry air takes place. The dirtied liquid is received at a holding tank corresponding to the holding tank 46. In FIG. 16 , this holding tank is denoted by the reference sign 234.

Dry air is released into the environment.

Another exemplary embodiment of a suction cleaning apparatus is a floor cleaning apparatus 236, as shown schematically in FIG. 17 .

The floor cleaning apparatus has a cleaning head 238, on which there is arranged at least one cleaning roller unit 240.

The cleaning roller unit comprises one or more rotating cleaning rollers, for example made of a textile material. During operation of the floor cleaning apparatus 236, the cleaning roller unit 240 is rotationally driven by a corresponding drive.

In particular, cleaning liquid is supplied to the cleaning roller unit 240, or cleaning liquid is supplied directly to the floor to be cleaned. Usually, the cleaning liquid is fresh water, optionally containing a surfactant-based cleaning agent additive.

The cleaning roller unit 240 forms an acting device for an area to be cleaned.

Dirty liquid is extracted from the cleaning roller unit 240. A liquid separator corresponding to the liquid separator 52 is provided for this purpose. This is arranged, for example, on a body 242, on which the cleaning head 238 is, in turn, seated.

The air-laden dirty fluid is introduced in one or more channels from the cleaning roller unit 240 into the liquid separator 52. The air-laden dirty fluid is indicated by reference sign 244 in FIG. 17 .

The separation of air and dirtied liquid takes place at the liquid separator 52.

The release of dry air is indicated by the arrow with reference sign 246.

Here, the liquid separator also forms the suction unit device for sucking in the air-laden dirty fluid 244.

Separated liquid is introduced into a holding tank 248 for liquid.

In particular, the floor cleaning apparatus 236 is hand-held. It is provided with a holding device 250 having a bow-type handle 252. A standing operator can hold the holding device 52 and guide the cleaning head 238 over the floor to be cleaned.

LIST OF REFERENCE SIGNS

-   10 suction cleaning apparatus -   12 housing -   14 housing interior -   16 first housing wall -   18 second housing wall -   20 first intermediate wall -   22 second intermediate wall -   24 top side -   26 front side -   28 bottom side -   30 rear side -   32 handle -   34 handle opening -   36 first web -   38 second web -   40 third web -   42 wall -   44 switch -   46 holding tank for liquid -   48 direction -   50 suction unit device -   51 area to be cleaned -   52 liquid separator -   54 chamber -   56 peripheral wall -   58 chamber interior -   60 first end cover -   62 second end cover -   64 axis -   66 rotor -   68 rotary bearing -   70 rotational axis -   72 drive motor -   74 motor housing -   76 battery device -   78 central tube -   80 interior -   82 region -   84 collar -   86 annular web -   88 main flow direction -   90 deflection -   92 blade -   94 outlet opening for liquid -   96 acting device -   98 inlet opening -   100 delimiting wall -   102 wedge element -   104 wedge tip -   106 direction of rotation -   108 connection piece -   110 bottom wall -   112 side wall -   114 cover wall -   116 counter element -   118 longitudinal direction -   120 first region -   122 second region -   124 third region -   126 annular space -   128 dip tube -   130 outlet opening -   132 end face -   134 collar -   136 air discharge device -   138 a inner delimiting wall -   13 8 b outer delimiting wall -   140 dipping edge -   142 suction opening -   144 channel -   146 filter (coarse dirt filter, fluff filter) -   148 deflection region -   150 filter holder -   152 removal direction -   154 handle element -   156 outlet opening -   158 channel -   160 double-lined arrow -   162 wavy arrow -   164 air supply device -   166 gap -   168 opening -   170 arrows -   172 dry air flow -   174 control device -   176 liquid separator -   178 chamber -   180 peripheral wall -   182 axis -   184 outlet opening -   186 supply region -   188 liquid separator -   190 chamber -   192 peripheral wall -   194 axis -   196 first region -   198 second region -   200 outlet opening -   202 supply region -   204 first inclined region -   206 second inclined region -   208 liquid separator -   210 chamber -   212 dip tube -   214 axis -   216 liquid separator -   218 chamber -   220 dip tube -   222 dip tube -   224 central tube -   226 window cleaner -   228 acting device -   230 wiper -   232 inlet opening -   234 holding tank -   236 floor cleaning apparatus -   238 cleaning head -   240 cleaning roller unit -   242 body -   244 air-laden dirty fluid -   246 air -   248 holding tank -   250 holding device -   252 bow-type handle 

1. A suction cleaning apparatus comprising an acting device for acting on an area to be cleaned; a suction unit device for generating a suction flow; and a liquid separator; wherein the liquid separator has a chamber having a peripheral wall and a rotor which is arranged in the chamber and is rotatable about a rotational axis; wherein at least one outlet opening for liquid is arranged on the peripheral wall; and wherein a holding tank for liquid is provided which is fluidically connected to the at least one outlet opening for liquid.
 2. The suction cleaning apparatus in accordance with claim 1, wherein the rotor is part of the suction unit device and is arranged and configured such that it effects a negative pressure during operation of the suction cleaning apparatus to generate the suction flow.
 3. The suction cleaning apparatus in accordance with claim 1, wherein the rotor is arranged and configured such that the liquid separator is formed as a centrifugal separator and, during operation of the suction cleaning apparatus, flings liquid droplets radially outwardly toward the peripheral wall.
 4. The suction cleaning apparatus in accordance with claim 1, wherein at least one of the following applies: the rotational axis is oriented parallel at least to a partial region of the peripheral wall; the chamber is cylindrical or conical-portion-shaped at least in a partial region; the chamber is at least approximately rotationally symmetrical to the rotational axis.
 5. The suction cleaning apparatus in accordance with claim 1, wherein at least one of the following applies: a mouth normal of the at least one outlet opening for liquid is oriented transversely to the rotational axis; the at least one outlet opening for liquid is in the form of a slot; the at least one outlet opening for liquid or a supply region to the at least one outlet opening for liquid extends over at least 50% of a height of the peripheral wall; during proper operation of the suction cleaning apparatus for cleaning a surface that is horizontal with respect to the direction of gravity, at least one of i) the at least one outlet opening for liquid and ii) the holding tank for liquid lies below the rotational axis with respect to the direction of gravity.
 6. The suction cleaning apparatus in accordance with claim 1, wherein the at least one outlet opening for liquid is associated with a supply region, in particular with at least one of the following: the supply region has at least one flow region which leads to the at least one outlet opening for liquid, wherein, when cleaning a surface which is horizontal with respect to the direction of gravity, a flow of liquid toward the at least one outlet opening in the flow region is driven by gravity; at the supply region, the peripheral wall is inclined relative to the rotational axis; the supply region is funnel-shaped.
 7. The suction cleaning apparatus in accordance with claim 1, comprising a drive motor, which is associated with the chamber and which drives a rotational movement of the rotor.
 8. The suction cleaning apparatus in accordance with claim 1, comprising a central tube, which protrudes into the chamber and which is fluidically connected to the acting device, with an air-laden dirty fluid being introduced into the chamber by the central tube.
 9. The suction cleaning apparatus in accordance with claim 8, wherein at least one of the following applies: the central tube is positioned coaxially with the rotational axis; the rotor contacts the central tube or is spaced apart from the central tube by a gap; the rotor has a central region to which the air-laden dirty fluid is supplied axially by the central tube, with a radial deflection taking place at or adjacently to the central region; an annular space is formed in the chamber around the central tube; the chamber has an inlet opening for an air-laden dirty fluid, said inlet opening being formed on the central tube; a ratio of an inner diameter of the central tube in the supply of the air-laden dirty fluid to the rotor to an outer diameter of the rotor is in the range between 0.1 and 0.5.
 10. The suction cleaning apparatus in accordance with claim 8, wherein an air supply device is associated with the rotor, by which false air is suppliable to the rotor.
 11. The suction cleaning apparatus in accordance with claim 10, wherein at least one of the following applies: the air supply device comprises one or more gaps between the central tube and the rotor; the air supply device comprises one or more openings of the central tube to an interior of the chamber; at least one false air valve is arranged on the central tube.
 12. The suction cleaning apparatus in accordance with claim 1, wherein at least one dip tube is associated with the chamber for removing air and in particular dry air, with at least one outlet opening for air being formed on the at least one dip tube.
 13. The suction cleaning apparatus in accordance with claim 12, wherein at least one of the following applies: the at least one dip tube is oriented parallel or transverse to the rotational axis; the at least one dip tube is at least one of i) oriented parallel to and ii) spaced apart from a central tube by which an air-laden dirty fluid is introduced into the chamber; an end face of the at least one dip tube is at least one of i) spaced apart from an end face of the central tube and ii) spaced apart from the rotor; the at least one dip tube has a smaller length than the central tube; the at least one outlet opening for air is spaced apart from the peripheral wall; the at least one dip tube has circular-segment-shaped delimiting walls adapted to the peripheral wall; the at least one dip tube is positioned above the rotational axis with respect to the direction of gravity during proper operation of the suction cleaning apparatus for cleaning a surface that is horizontal with respect to the direction of gravity; the at least one dip tube has an extension in the form of a collar at one end face, which extension is in particular sharp-edged.
 14. The suction cleaning apparatus in accordance with claim 12, wherein the at least one dip tube is fluidically connected to the acting device and the acting device has at least one outlet opening for air.
 15. The suction cleaning apparatus in accordance with claim 1, wherein the chamber has a first end cover and a second end cover between which the peripheral wall lies.
 16. The suction cleaning apparatus in accordance with claim 15, wherein at least one of the following applies: the first end cover is positioned facing the acting device; a central tube runs through the first end cover toward the rotor or the central tube is seated on the first end cover; at least one dip tube runs through the first end cover for removing air from the chamber or the at least one dip tube is seated on the first end cover; the first end cover is oriented transversely and in particular perpendicularly to the rotational axis.
 17. The suction cleaning apparatus in accordance with claim 15, wherein at least one of the following applies: the rotor is adjacent to the second end cover and in particular closer to the second end cover than to the first end cover; with respect to an extension of the rotational axis, a drive motor is arranged behind the second end cover; a rotary bearing for the rotor is arranged on the second end cover; the second end cover is oriented transversely to the rotational axis.
 18. The suction cleaning apparatus comprising an acting device for acting on an area to be cleaned, a suction unit device for generating a suction flow, and a liquid separator, or in accordance with claim 1, wherein a filter is arranged between the acting device and the liquid separator.
 19. The suction cleaning apparatus in accordance with claim 18, wherein the filter is formed as a coarse dirt filter.
 20. The suction cleaning apparatus in accordance with claim 18, wherein the filter is arranged upstream of a chamber of the liquid separator.
 21. The suction cleaning apparatus in accordance with claim 18, wherein, with respect to a flow direction of an air-laden dirty fluid, the filter is arranged upstream of a central tube by which the air-laden dirty fluid is introduced into a chamber.
 22. The suction cleaning apparatus in accordance with claim 18, wherein a flow path for an air-laden dirty fluid from the acting device to a chamber of the liquid separator has a deflection region, and wherein the filter is arranged at the deflection region.
 23. The suction cleaning apparatus in accordance with claim 18, wherein the filter is arranged so to be removable from the suction cleaning apparatus and, in particular, can be removed from a housing outer side.
 24. The suction cleaning apparatus in accordance with claim 1 wherein, during operation of the suction cleaning apparatus, the rotor is operated at a rotational speed at which foam is broken down in the chamber.
 25. The suction cleaning apparatus in accordance with claim 1, wherein, during operation of the suction cleaning apparatus, the rotor has a rotational speed in the range between 1,000 revolutions per minute and 100,000 revolutions per minute.
 26. The suction cleaning apparatus in accordance with claim 1, wherein an outer diameter of the rotor lies in the range between 20 mm and 150 mm.
 27. The suction cleaning apparatus in accordance with claim 1, wherein the at least one outlet opening for liquid is sharp-edged at least at a delimiting wall.
 28. The suction cleaning apparatus in accordance with claim 27, wherein the at least one outlet opening for liquid is wedge-shaped with an acute wedge angle at least on one side.
 29. The suction cleaning apparatus in accordance with claim 1, wherein the acting device is or comprises at least one of the following: a wiper for liquid; a cleaning roller, which is covered with a textile material, for example; a suction nozzle; a dipping edge for a textile material; at least one suction opening for an air-laden dirty fluid and at least one channel, which leads to the liquid separator; at least one outlet opening for air and at least one channel, which leads to the liquid separator.
 30. The suction cleaning apparatus in accordance with claim 1, comprising a battery device for supplying electrical energy.
 31. The suction cleaning apparatus in accordance with claim 30, comprising a housing which has a handle opening, the battery device being arranged on a web which delimits the handle opening.
 32. The suction cleaning apparatus in accordance with claim 30, wherein a drive motor for the rotor follows the chamber and wherein the battery device follows the drive motor.
 33. The suction cleaning apparatus in accordance with claim 1, comprising a housing with a bottom side, and wherein the holding tank for liquid is seated removably on the bottom side.
 34. The suction cleaning apparatus in accordance with claim 1, wherein the holding tank for liquid has a first region, a second region following the first region, and a third region following the second region, with liquid being introduced from the at least one outlet opening for liquid via the second region.
 35. The suction cleaning apparatus in accordance with claim 34, wherein the first region and the third region each have a greater height than the second region, and in particular wherein the cross-section of the holding tank for liquid is C-shaped or U-shaped.
 36. The suction cleaning apparatus in accordance with claim 34, wherein the third region is positioned opposite a drive motor when the suction cleaning apparatus is fitted with a holding tank for liquid.
 37. The suction cleaning apparatus in accordance with claim 34, wherein the first region is positioned facing the acting device when the suction cleaning apparatus is fitted with a holding tank for liquid.
 38. The suction cleaning apparatus in accordance with claim 1, said suction cleaning apparatus being embodied as a hand-held or hand-guided suction cleaning apparatus.
 39. The suction cleaning apparatus in accordance with claim 1, said suction cleaning apparatus being formed as an extraction apparatus or spray extraction apparatus for textile materials.
 40. A method for operating a suction cleaning apparatus, said cleaning apparatus comprising an acting device for acting on an area to be cleaned, a suction unit device for generating a suction flow, and a liquid separator, wherein the liquid separator has a chamber having a peripheral wall and a rotor which is arranged in the chamber and is rotatable about a rotational axis, wherein at least one outlet opening for liquid is arranged on the peripheral wall, and wherein a holding tank for liquid is provided which is fluidically connected to the at least one outlet opening for liquid, said method comprising generating a negative pressure by a rotor of the liquid separator, sucking an air-laden dirty fluid into a chamber of the liquid separator, wherein the liquid separator acts as a centrifugal separator with the rotating rotor, and discharging separated liquid to a holding tank for liquid via at least one outlet opening for liquid, which is arranged on the peripheral wall of the chamber.
 41. The method in accordance with claim 40, wherein an air-laden dirty fluid sucked in is passed through a filter before entering the liquid separator.
 42. The method in accordance with claim 40, wherein dry air is discharged from the chamber by at least one dip tube. 